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VM TCP/IP Translation Tables

VM TCP/IP uses translation tables to control the way that character data is translated between ASCII and EBCDIC or, in some cases, between two different forms of EBCDIC.

Translation tables are stored as binary files on disk with a file type of TCPXLBIN. The file name usually indicates a country or a pair of code pages. IBM provides a large selection of over 200 translation tables covering various geographies, languages, and operating systems.

Each VM TCP/IP client or server program determines which translation table to use by following these rules, in order:

  1. Use the translation table name that has been specified in a server configuration statement or by the client. If the translation table does not exist, the program stops.

  2. Use a "preferred" translation table, if one exists.

    Program Preferred table
    TELNET clientTELNET TCPXLBIN
    Telnet serverSTLINMOD TCPXLBIN
    FTP clientFTP TCPXLBIN
    FTP serverSRVRFTP TCPXLBIN
    TFTP clientTFTP TCPXLBIN
    NFS serverVMNFS TCPXLBIN
    SMTP serverSMTP TCPXLBIN
    LPR clientLPR TCPXLBIN
    LPD serverLPD TCPXLBIN

  3. Use the translation table called STANDARD, if it exists. A version of STANDARD TCPXLBIN is supplied by IBM. It is equivalent to the 7-bit built-in translation table.

  4. Use a built-in translation table supplied by IBM. This table is a 7-bit non-reversible translation. All extended ASCII characters with values greater than 0x7F are lost when they are converted to EBCDIC.

All translation tables included with VM TCP/IP, with the exception of STANDARD, are 8-bit tables. These 8-bit tables are reversible mappings that maintain the uniqueness of each character. No characters are lost during translation. However, 8-bit tables should not be used in situations where their communications partner (client or server) is known to use the high-order bit in each octet (byte) to indicate parity.

TCP/IP translation tables can be created by copying an IBM-supplied translation table or by using the CONVXLAT command. For more information, see "Using Translation Tables" in VM/ESA: TCP/IP Planning and Customization.